Numerous scientific and commercial processes involve the interaction of one or more compounds (often in liquid form or present in a liquid carrier or the like) with one or more surface area. Such surfaces can be functionalized to perform specific actions, e.g., to bind certain compounds, to indicate the presence of specific compounds, to catalyze specific reactions, to change the relative temperature of compounds/liquids/gasses/etc. that come into contact with the surface, to prevent binding to the surface, to release drugs, etc. For example, common uses of surface/compound interactions include separation columns or filters, heat exchanges, microarray assays, chemical sensors, bio-sensors, medical devices, etc. Other examples are replete throughout the literature and, indeed, throughout everyday usage.
In almost all instances, however, the efficiency or use of such processes and devices is limited, at least in part, by the area of the surface which is in contact with the one or more compound or desired constituent (e.g., the liquid, gas, etc.). This limitation is true in several aspects. First, space limitations are of concern. For example, only a finite number of functional units (e.g., antibodies, catalysts, etc.) can physically exist per unit area of a surface (i.e., within a certain footprint). Thus, the action to be accomplished can be limited by the number of functional units, which is in turn limited by the unit area or footprint of the surface which contains the functional units. One answer to such problems is to increase the unit area or size of the footprint involved. However, besides being inelegant, such response is often problematic due to cost restraints and size limitations imposed on the footprint itself (e.g., the reaction might need to be performed in a limited space in a device, etc.)
Second, such processes and devices are often also limited in terms of resolution or sensitivity. For example, in situations such as detection, the activity allowing detection of a compound or constituent can sometimes be ‘weak’ or difficult to detect. Alternatively, the compound may only briefly or imperfectly interact with a moiety on the surface (i.e., one involved in the detection process). In such situations, even increasing the footprint size might not be enough to improve detection, since a weak response is still a weak response when spread out over a larger area (i.e., the response per unit area would still be the same). A similar problem can occur in column reactions and can result in faint or diffuse bands.
In a number of conventional or current applications, the surface area of a matrix is increased by providing the material making up the surface with a number of holes or pores. By providing the matrix as a porous solid, rather than just a solid surface, one increases the amount of available surface area without increasing the amount of space that the material occupies (i.e., the footprint size). While such porous configurations do increase the surface area of the matrix, a number of issues arise to limit the effectiveness of such measures. In particular, due to the tortuous and narrow nature of the paths offered by these pores, materials are typically prevented from being actively flowed into contact with the relevant surfaces in the interior of the pores. As a result, materials must drift into contact with these surfaces via diffusion, which is limited by available time, and also by the size of the molecules of interest, e.g., larger molecules diffuse more slowly. Even in cases where porous networks do allow flow-through, the narrow and elongated nature of such networks results in back pressures that typically force materials to flow through less tortuous paths, e.g., around the matrix entirely. Thus, in other words, a third problem often arises in the “path” involved in reactions, etc. For example, in some current traditional separation/detection devices, an analyte needs to wind its way through a complex pathway in order to reach the appropriate detection element or to achieve separation or the like. Such tortuous paths can increase processing times (i.e., decrease throughput).
A final, but not trivial, problem concerns cost. Larger devices/surfaces/structures that are needed, e.g., to allow inclusion of greater numbers of areas or functional units, can be quite expensive.
A welcome addition to the art would be surfaces having enhanced surface areas and structures/devices comprising such, as well as methods of using enhanced area surfaces and devices, which would have the benefits of, e.g., increased functionality per unit area, short and/or non-tortuous processing paths and the like. The current invention provides these and other benefits which will be apparent upon examination of the following.